The S&P 500 index and Nasdaq Composite Index fell on Tuesday for the sixth straight session as Democratic presidential nominee Hillary Clinton's lead in the polls over Republican Donald Trump narrowed. The S&P 500 [s:spx] fell 14.59 points, or 0.7%, to 2,111.57, with nine of its 10 sectors in the red. The Nasdaq shed 35.56 points, or 0.7%, to 5,153.58, largely due to sharp declines in several biotech stocks, as well as a 15% drop in shares of Tronc. Inc. after USA Today-owner Gannett Inc. abandoned its pursuit of the rival media company. The Dow Jones Industrial Average dropped 105.39 points, or 0.6%, to 18,037.10, with 27 of its 30 components ending lower. The blue-chip benchmark has fallen for four consecutive sessions.